JPS5930240A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium havin improved wear resistance, durability and antistatic properties as well as improved traveling stability by forming a resin layer contg. TiO and powder having specified Mohs hardness on one side of a support opposite to a magnetic layer. CONSTITUTION:A layer contg. TiO having about 0.01-1mum average grain size and nonmagnetic powder having about 0.01-1mum average grain size and 3-6 Mohs hardness such as CaF or CaCO3 powder in 1/4-4/1wt. ratio of TiO/CaF or the like by about 40-100pts.wt. in total of TiO and CaF or the like per 100pts.wt. resin binder is formed on one side of the support of a magnetic recording medium opposite to the magnetic layer. Thus, a magnetic tape having improved wear resistance, durability and antistatic properties as well as superior electromagnetic conversion characteristics, especially Y-S/N ratio is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, by providing a resin layer containing titanium oxide and powder having a Mohs hardness of 3 to 6 on the base surface opposite to the magnetic layer. An object of the present invention is to provide a magnetic recording medium which has excellent wear resistance, durability, antistatic properties, and running stability, and which can also improve electromagnetic conversion characteristics.

In recent years, rapid technological innovations in home video tape recorders have led to the development of long-duration recording modes, and the magnetic tape used in such recording and reproducing devices is required to have excellent electromagnetic conversion characteristics. The base film used as a support for such magnetic tapes has a smooth surface.

However, it has been found that magnetic tapes constructed by coating such a smooth base film with a magnetic layer have problems such as poor abrasion resistance and poor running stability. As a result of conducting various studies to solve the above-mentioned problems, researchers have developed a method of applying a mixed solution containing titanium oxide, non-magnetic powder with a Mohs hardness of 3 to 6, and a binder resin to the base surface opposite to the magnetic layer. -Titanium oxide and Mohs hardness 3~
By providing the non-magnetic powder-containing resin layer of No. 6, the magnetic recording medium has excellent antistatic effect and wear resistance.
They discovered that it has excellent durability, excellent running properties, and excellent electromagnetic conversion characteristics.

In addition, the content of titanium monoxide and non-magnetic powder having a Mohs hardness of 3 to 6 in the resin layer provided on the base surface opposite to the magnetic layer is monoxide per 100 parts by weight of the resin in the resin layer. The total of titanium and non-magnetic powder with a Mohs hardness of 3 to 6 is 40
It has also been found that preferred properties are obtained when the ratio of (-titanium oxide)/(non-magnetic powder with a Mohs hardness of 3 to 6) is 10 to 100 parts by weight.

Examples of the magnetic recording medium according to the present invention will be described below.

Example 1 ■ Contains 100 parts by weight of γ-F6203, 1 part by weight of lecithin, 10 parts by weight of vinyl chloride-vinyl acetate-vinyl alcohol copolymer, 10 Jii parts of polyurethane elastomer,
A mixture of 300 parts by weight of a mixed agent of methyl ethyl ketone, toluene and methyl imbutyl ketone was mixed and dispersed in a sand mill for about 20 hours, and 5 parts by weight of a polyincyanate curing agent was added thereto to make a magnetic paint. It is coated on a support made of a polyester film having a thickness of 145 μm and calendered.

In addition, 5 parts by weight of titanium monoxide with an average particle diameter of 0.01 to 1 μm, 25 parts by weight of CaF with an average particle diameter of 0.01 to 1 μm, 5 parts by weight of nitrified cotton, 10 parts by weight of polyurethane elastomer, etc., and 25 parts by weight of methyl ethyl ketone. 10 parts by weight of Siquahexanone are thoroughly mixed and dispersed using a sand mill, and this mixed solution is applied to a predetermined thickness, for example, 1 μm thick, on the opposite side of the support coated with the magnetic paint,
dry.

The product obtained in this way is heated at 60'C for 24 hours, for example.
The material is left for a period of time to undergo a curing reaction, and then slit into 10-inch widths to obtain, for example, a magnetic tape for a video tape recorder.

Example 2 A magnetic tape is obtained in the same manner as in Example 1 except that the TiO powder and the τ2 powder in Example 1 are 3 parts by weight and 7 parts by weight, respectively.

Example 3 A magnetic tape is obtained in the same manner as in Example 1 except that the CaF powder in Example 1 is replaced with CaQ) powder.

Comparative Example 1 A magnetic tape was obtained in the same manner as in Example 1, except that the TiO and 0F2-containing binder-resin layer in Example 1 was not provided.

Comparative Examples 2 and 3 Magnetic tapes were obtained in the same manner as in Example 1 except that 10 parts by weight of Example 5 powder or 10 parts by weight of C-2 powder were used in place of T10 and CaF2 in Example 1.

Regarding the magnetic tape thus obtained, Y-8/
N, FM output, surface resistivity of non-magnetic surface, initial and 20
Measuring the coefficient of dynamic friction (chu) after 0 repeated runs and the degree of damage to the non-magnetic surface after 200 repeated runs.
As shown in the table.

Table Y-3/N, FM output is the deviation value from the standard tape.As can be seen from this result, the resin layer containing TiO powder and powder with a Mohs' hardness of 3" to 6 is opposite to the magnetic layer. The magnetic tape provided on the - side support surface has electromagnetic conversion characteristics,
In particular, Y-8/N has become noticeably better.
Furthermore, even after repeated running, the coefficient of dynamic friction hardly changes, and the running performance is good.

In addition, there is almost no damage caused by repeated driving,
It has excellent wear resistance and durability, and also has low surface resistivity and is effective in preventing static electricity.
It is also resistant to dirt and dust.

In addition, since it contains TiO powder, it has excellent light blocking properties, and even when used in a recording/playback device equipped with a tape edge detection mechanism such as an optical sensor, the tape edge detection mechanism may malfunction. do not have.

The thickness of the resin layer containing titanium oxide, etc.
A thickness of approximately 2 μm is desirable.

As shown in the above, the magnetic recording medium according to the present invention is provided with a magnetic layer on one side of a support and a resin layer containing titanium monoxide and powder with a Mohs hardness of 3 or more and less than 6 on the other side. Therefore, the magnetic recording medium has excellent abrasion resistance and durability, is less likely to be scratched, is also excellent in anti-static properties, is resistant to dirt and dust, has excellent running properties, and is Y -8/
It has features such as improved electromagnetic conversion characteristics such as N.

Patent applicant: Victor Japan Co., Ltd.

Claims (1)

[Claims] A magnetic recording medium characterized in that a magnetic layer is provided on one side of a support, and a resin layer containing titanium monoxide and powder having a Mohs hardness of 3 or more and less than 6 is provided on the other side.